A 38yo male with history of diverticulitis complicated by sepsis presented to the ED with lower quadrant abdominal pain. He noted that the pain started 2 weeks ago and became worse. He reported normal bowel movements in the morning, denied fever/chills, nausea, vomiting, or genitourinary symptoms. A recent colonoscopy was notable for moderate sigmoid diverticulosis and a 4mm sessile sigmoid polyp that was resected.
Past medical history: Diverticulitis, ADHD, eczema, insomnia, loose stools
A bedside ultrasound was performed, and the following image was obtained:
Figure 1: Diverticula with bowel wall edema
Uncomplicated acute diverticulitis characteristics on ultrasound are:
thickened bowel wall >5mm
presence of diverticula with focal outpouching or bowel wall discontinuity
noncompressible pericolic fat inflammation with hyperechogenic halo around bowel serosa
sonographic tenderness with compression
Outcome:
General surgery was consulted for possible surgical evaluation, which was deferred after findings on CT noted to be non-surgical. Patient was sent home with ciprofloxacin 500mg BID for 7 days and metronidazole 500mg TID for 7 days. Patient was also educated on return precautions.
References:
Nazerian P, Gigli C, Donnarumma E, et al. Diagnostic accuracy of point-of-care ultrasound integrated into clinical examination for acute diverticulitis: a prospective multicenter study. Ultraschall der Med 2021;42(6):614–22. English.
Cohen A, Li T, Stankard B, et al. A prospective evaluation of point of care ultrasonographic diagnosis of diverticulitis in the emergency department. Ann Emerg Med 2020;76(6):757–66.
Damewood, Sara et al. “Gastrointestinal and Biliary Point-of-Care Ultrasound.” Emergency medicine clinics of North America vol. 42,4 (2024): 773-790. doi:10.1016/j.emc.2024.05.006
A 37 year old male with a past medical history of ulcerative colitis, now status-post total abdominal colectomy with a creation of end ileostomy, left-sided ureteral lysis due to retroperitoneal fibrosis, robotic-assisted proctectomy with creation of an ileoanal pouch and diverting loop ileostomy, extensive lysis of adhesions and right-sided ureterolysis, and ileostomy takedown in 2024 presents to the ED with diffuse abdominal pain that began this morning and sweats beginning last night. The pain was 4/10 with rest, 7/10 with standing, and 8/10 with ambulation. The pain radiated to the right shoulder this morning while lying in bed. He denied nausea and vomiting. He endorsed intermittent testicular pain, reduced oral intake, and decreased voids, but urinated and defecated without pain. Did not report any abnormal concerns with stool input through anastomosis.
Physical Exam showed a soft, flat, non-distended abdomen. A surgical scar was present. There was generalized abdominal tenderness and guarding throughout the abdomen with palpation, without rebound or rigidity. He had tenderness in the lower quadrants > upper quadrants, left > right. There was no hernia present. The remainder of the physical exam was unremarkable.
Labs: WBC 16.9
A bedside ultrasound was performed on the abdomen:
Figure 1: Pneumoperitoneum
Figure 2: Pouchitis
Discussion:
Pneumoperitoneum, a critical condition marked by the presence of free air in the abdominal cavity, typically arises from a perforated hollow viscus and is a rare yet serious cause of acute abdominal pain1,2. This condition requires immediate surgical intervention due to its potential for high mortality. Detecting serious conditions based on abdominal pain alone during physical examinations is challenging due to low sensitivity. Differential diagnoses for acute abdominal pain may include inflammatory bowel disease complications, intra-abdominal abscesses, perforations, bowel obstructions, mesenteric ischemia, and pancreatitis.
While abdominal X-ray and computed tomography of the abdomen are considered as more conventional standards for imaging, ultrasound also serves as a rapid, radiation-free diagnostic tool for detecting gastrointestinal perforations3. The diagnostic performance of ultrasonography for pneumoperitoneum has shown to have a sensitivity of 93%, accuracy of 90%, specificity of 64%, and positive predictive value of 97%, versus plain radiography (79%, 77%, 64%, and 96%, respectively)4.
One key ultrasonographic finding in cases of gastrointestinal perforation is the presence of the peritoneal stripe sign, which shows equidistant, horizontal or vertical reverberations posterior to the abdominal wall and can extend to the lower edge of the monitor, creating a striped pattern of alternating dark and light hyperechoic lines. A “comet tail” appearance may also be present as a result of reverberation artifacts caused by pockets of free air, which acts as a barrier to ultrasound waves2,5.
An additional technique used in ultrasound for detecting a pneumoperitoneum is the "shifting phenomenon." This involves repositioning the patient to observe the movement of air and the peritoneal stripe sign within the peritoneal cavity, confirming the presence of free air6. The "scissors maneuver" further confirms this technique by placing a linear probe in the right epigastric region without abdominal compression; reverberation artifacts are observed and manipulated by pressing and releasing the caudal end of the probe, showing movement of the free air and reverberation artifacts away from the anterior liver5.
The use of ultrasound not only confirmed the presence of pneumoperitoneum, but also allowed for immediate surgical intervention, underscoring its high sensitivity and the crucial impact of rapid assessment capabilities in emergency settings. Point-of care ultrasound should be considered as a potential first-line form of diagnostic imaging for abdominal perforation.
References:
Nazerian, P., Tozzetti, C., Vanni, S. et al. Accuracy of abdominal ultrasound for the diagnosis of pneumoperitoneum in patients with acute abdominal pain: a pilot study. Crit Ultrasound J 7, 15 (2015). https://doi.org/10.1186/s13089-015-0032-6
Chao, A., Gharahbaghian, L., & Perera, P. (2015). Diagnosis of pneumoperitoneum with bedside ultrasound. The western journal of emergency medicine, 16(2), 302. https://doi.org/10.5811/westjem.2014.12.24945
Jiang L, Wu J, Feng X. The value of ultrasound in diagnosis of pneumoperitoneum in emergent or critical conditions: A meta-analysis. Hong Kong Journal of Emergency Medicine. 2019;26(2):111-117. doi:10.1177/1024907918805668
Bacci, M., Kushwaha, R., Cabrera, G., & Kalivoda, E. J. (2020). Point-of-Care Ultrasound Diagnosis of Pneumoperitoneum in the Emergency Department. Cureus, 12(6), e8503. https://doi.org/10.7759/cureus.8503
Taylor, M.A., Merritt, C.H., Riddle, P.J. et al. Diagnosis at gut point: rapid identification of pneumoperitoneum via point-of-care ultrasound. Ultrasound J 12, 52 (2020). https://doi.org/10.1186/s13089-020-00195-2
Yum, J., Hoffman, T., & Naraghi, L. (2021). Timely Diagnosis of Pneumoperitoneum by Point-of-care Ultrasound in the Emergency Department: A Case Series. Clinical practice and cases in emergency medicine, 5(4), 377–380. https://doi.org/10.5811/cpcem.2021.4.52139
A 40 year old male presented with a 4 day history of right lower quadrant pain. He reported that the pain was at its worse when it started but gradually improved. When in the ED he noted only minimal discomfort without the help of analgesics. He denied ever having anorexia, fever, chills, nausea, vomiting, GU complaints. During examination, he had moderate tenderness to palpation in the right lower quadrant without rebound or guarding.
Vitals: T 97.7F BP 130/77 HR 66 RR 16 SP02 100%
An abdominal ultrasound of the RLQ was performed and the following images were seen. What do you see and what is your most likely diagnosis?
Answer and Learning Points
Answer
In both the longitudinal and transverse views, you see a tubular structure in the right lower quadrant that is non- compressible, greater than 6mm (measures 15.6 mm), and lacks peristalsis. You can also appreciate some dependent free fluid around the appendix. These findings are consistent with the diagnosis of acute appendicitis.
CT abdomen/pelvis showed a retrocecal appendix with finding of acute uncomplicated appendicitis. No bowel obstruction or intra-abdominal/pelvic abscesses. Labs showed a slight leukocytosis to 14, otherwise were reassuring. Patient was given a dose of Zosyn in the emergency department and take to the OR for appendectomy by general surgery.
Learning Points
Appendicitis is the most common abdominal surgical emergency that presents to the ED in western countries [1].
The sensitivity and specificity of ultrasound for the diagnosis of appendicitis appears to be around 86% and 81%, respectively, based on results from older studies [2].
Ultrasound can be used to diagnosis acute appendicitis and may be the imaging modality of choice in certain patient populations such as pregnant women and children [3].
To obtain images you can use either the linear or curvilinear probe. Ask the patient to point where exactly they hurt and place the probe there. If you don’t see it you can use the landmark of the iliac crest (most lateral), psoas muscle (posterior), and iliac artery (most medial). Move superior and inferior along the iliac artery and the appendix should be just anterior to iliac artery. If you still haven’t found it, “lawnmower” along the right lower quadrant. Look for a tubular, blind ended pouch that has no peristalsis. It should be compressible and measure <6mm in AP diameter [4].
References
Caterino, S., et al. Acute abdominal pain in emergency surgery. Clinical epidemiologic study study of 450 patients. Ann Ital Chir. 1997; 68: 807-817.
Lim H, Bae S, Seo G: Diagnosis of acute appendicitis in pregnant women: value of sonography. AJR Am J Roentgenol 1992;159(3): 539–542.
Excerpt From: Mike Mallin & Matthew Dawson. “Introduction to Bedside Ultrasound: Volume 2.” Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 18th, 2020.
